This invention relates to an apparatus for making ice blocks comprising a frame, a hollow body fixedly mounted on this frame and having downwardly projecting parts, means for circulating refrigerating fluid through said hollow body, means for circulating heating fluid through said hollow body, a small tray, a mechanism bringing said small tray from an uppermost position around the above said projecting parts to a lowermost position and conversely, a water supply line that opens into said tray, means that open and close said water supply line, and elements that control the said means and the said mechanism in such a way that: the means for circulating the refrigerating fluid through the body are in operation while the tray is in its uppermost position, the mechanism brings the tray from its uppermost position into its lowermost position when ice has formed on the projecting parts, the means for circulating heating fluid through the body come into operation after ice has formed on the projecting parts, and the water supply line is opened after ice has formed on the projecting parts.
The elements that control the mechanism and the means for circulating the fluids through the hollow body comprise e.g. a microswitch which is closed when a stirrer meets with resistance offered by the ice that has formed on the above named projecting parts, which then are in the tray that is occupying its uppermost position.
An apparatus comprising a microswitch that is closed when agitating members are impeded by the ice that has formed on projecting parts is known from the U.S. Pat. No. 3,027,731.
In practically known apparatus of the kind referred to, closing of such microswitch causes to stop the circulation of the refrigerating fluid and to start the circulation of the heating fluid and causes also the action of the mechanism that first brings the small tray from its uppermost position into its lowermost position and then from its lowermost position into its uppermost position. Likewise, closing of the microswitch brings about the opening of the water supply line so that water flows into the tray.
In these known apparatus the mechanism that brings the tray from an uppermost to a lowermost position and conversely comprises a motor-speed reducer whose power is sufficient to bring about the upward and downward movement of the tray. In some embodiments of the prior art the amount of water added to the tray is determined by a float, which closes the supply line as soon as enough water has been added.
In some other embodiments of the prior art the use of a float is avoided by allowing the added amount of water exceeding the required amount to flow away, but in these embodiments opening of the water supply line has to be controlled by a time switch, a programmator or any analogous mechanism.
The motor-speed reducer bringing about the movement of the tray, the float mechanism and the time switch or the analogous mechanism determining the opening period of the water supply line, are elements that complicate the apparatus for making ice blocks and strongly influence the cost price.
Apparatus comprising a small tray that is tilted automatically when ice blocks are formed and thereupon is again automatically filled with water are known from the U.S. Pat. Nos. 3,149,473 and 3,526,100. These prior art apparatus however, comprise an additional water-tank and a rather complicated mechanism for keeping the tray locked during the formation of the ice blocks and for keeping it unlocked after said formation, and for effecting the additional tank to be filled as well as for the water to overflow out of this tank into the tray.
On the contrary, in the apparatus according to the present invention essentially a downward movement of the tray is brought about by the fact that water is flowing into the tray when the ice blocks have been formed, and an upward movement is brought about by the fact that water is flowing away out of the tray being in its lowermost position.
Another apparatus comprising a tilting tray is known from the above cited U.S. Pat. No. 3,027,731. In this prior art apparatus tilting is effected by means of a rather sophisticated motor-driven mechanism.
According to the U.S. Pat. No. 2,443,203 a tilting movement, not of the tray wherein the ice blocks are formed but of a trough wherein this tray is fixedly mounted, is brought about by filling this trough with water. However, the trough is not filled automatically when ice blocks have been formed and the tray wherein the latter are formed continues to occupy the same place with respect to the refrigerating line.
The automatic flowing away of the water and the evacuation of the ice from a stationary tray are known from the Australian patent specification No. 460,312. In this prior art apparatus the tray is filled by means of a pump, which of course has to be driven by a motor, and the tray continues to permanently occupy the same place with respect to the refrigerating line.
Finally it has to be noticed that the upward and downward movement of a tray wherein ice blocks are formed is known as such from the U.S. Pat. No. 3,418,823. This upward and downward movement takes place continuously during the formation of the ice blocks and not after their formation, whereas the water supply unlimitedly takes place between two formation cycles of ice blocks.